1. Field of the Invention
This invention relates to an automobile junction box, in which the internal circuits utilize and share rectangular-shaped bus bars, and in which circuit changes are simplified.
2. Discussion of Background Information
In recent years, there has been a rapid increase in the number of automobile electrical equipments, and the number of circuits that are housed inside an automotive electrical connection boxes, especially junction boxes. Construction of such a high density of branch circuits requires numerous parts and a large amount of assembly time.
Among such automotive electrical connection boxes is junction box 1 of FIG. 15, for example, that has a multi-layered configuration of bus bars 5A-5D with intervening insulating plates 4A-4E between upper case 2 and lower case 3. The above-mentioned upper case 2 includes connector receptacles 2a, relay housings 2b, and fuse housings 2c to which connectors 6, relays 7, and fuses 8 are respectively attached so that their terminals are directly connected to tabs protruding from the bus bars or via relay terminals. Lower case 3 also includes connector receptacles 3a that connect to protruding tabs 5a of the bus bars. Bus bars 5A-5D that are attached to above mentioned insulating plates 4A-4E are stamped out of conductive metal boards into required circuit patterns.
As shown in FIGS. 16(A) and (B), vertical bus bars 5xe2x80x2 may also be housed inside upper case 2xe2x80x2 (3xe2x80x2), instead of the above bus bars 5A-5D. The above vertical bus bars 5xe2x80x2 are formed as ribbon-shaped conductive metal pieces formed to the required bent shapes.
In junction box 1 of FIG. 15, since the bus bars are stamped into circuit patterns, new bus bars must be manufactured if a change in the circuit is necessary. Therefore, the cost of dies to form the bus bars becomes very expensive as it becomes difficult to flexibly accommodate circuit changes. Also, the production yield for conductive metal boards is very poor, thus increasing the cost of manufacturing.
Using vertical bus bars 5xe2x80x2 as shown in FIG. 16, will improve the yield for manufacturing the conductive metal boards, because the bus bars are ribbon-shaped. However, bus bars that are formed and bent need to be inserted one by one into slots inside a case or between protruding guides. Therefore, such manufacturing still requires time and increases the cost.
Additionally, both of the junction boxes in FIGS. 15 and 16 have a configuration in which connectors, fuses, and relays are connected to bus bars in the internal circuits. Therefore, when there is a specification change that changes the connections between the fuses and relays and internal circuit, it is necessary to change the entire internal circuit, and it has been very difficult to easily accommodate circuit changes.
Furthermore, in the junction box of FIG. 15, when installing connectors, relays or fuse housings in vertically opposing positions, tabs that bend from the bus bars will overlap and cannot be extended. As a result, such tabs need to be installed at bus bars of different layers, thus increasing the number of bus bar layers. Due to such an increase in the number of bus bar layers, the height of the junction box will also increase and thus will no longer be compact.
The present invention is provided in view of the above-described problems. The first object of the invention is to provide for bus bars made to have a high yield rate for use in a junction box housing, automatic assembly of the bars into a case in a single automatic operation, and simplified circuit modification. The second object of the invention is to provide module units that contain the circuits in a junction box so that in the event of a change in a circuit that is connected to external circuits, fuses, or relays, the change is only made to the corresponding circuit without the need to modify the other circuit.
To address the above-described problems, the present invention provides a junction box that is divided into a base circuit part connected to an external circuit, and a fuse and/or relay circuit connection part, that incorporates a base module including the base circuit part and a fuse module including the above fuse connection circuit part and/or a relay module including the relay connection circuit, and that is assembled by combining these modules. The base circuit part of the base module is configured with rectangular vertical bus bars aligned in parallel in an internal part of a case, wherein the case incorporates multiple terminal housing compartments into which terminals for connection to external wire terminals are inserted, the terminals incorporating pairs of terminal grip ends that grip and connect to the vertical bus bars.
As described above, the junction box, according to the present invention, incorporates a base module including a base circuit part connected to an external circuit of external wires, and employs rectangular vertical bus bars as a circuit body for the base module. Unlike conventional vertical bus bars that are formed by bending, the vertical bars of the present invention are used xe2x80x9cas isxe2x80x9d in rectangular shape and are aligned in parallel inside a case. Thus, it is possible to get a 100% yield from a conductive metal board omitting the forming process, and to automatically assemble the internal case by installing the vertical bars in one operation.
In addition, the internal circuit of the junction box is divided into a base circuit part that is connected to an external circuit, and a fuse and/or relay connection circuit part, and the junction box incorporates a base module including the base circuit part, and a fuse module including the fuse connection circuit and/or relay module including the relay connection circuit. Because the junction box is assembled with these modules, if there are any specification changes in the fuse and/or relay connection circuit parts, it is only necessary to change the corresponding fuse and/or relay modules, thus simplifying the process for such specification changes. Conversely, if changes only to the connection circuit with the external wires are required, it is only necessary to change connection positions of the wires that are connected to the vertical bus bars of the base module, thus also simplifying the process for such circuit changes.
A terminal stop part that stops the terminal is installed on the inner surface of the individual terminal housing that is installed in the case of the base module. It is preferable to align the terminal housings in parallel and to have a retainer insertion orifice in the case, so that the terminals inserted in these terminal housings are secured with overlapping stops. By installing the double stop retainer, it is possible to prevent unplugging and to detect incomplete insertion of the terminals inside each terminal housing. Also, since the terminal housings are aligned in parallel, it is possible to automatically connect multiple wire terminals to vertical bus bars in one operation.
As described above, once all of the terminals from the external wires connected to the vertical bus bars inside the base module are inserted in the terminal housings, it is no longer necessary to have a conventional connection between the wire harness and junction box circuits. It also becomes possible to form a one-piece junction box and wire harness assembly that includes the above external wires.
The above terminal housing and/or connector receptacle are provided on both cases on the surfaces that oppose the aligned vertical bus bars, and both sides of the aligned vertical bus bars are gripped in the length direction and connected by the above wire end terminals. When a junction box is horizontally positioned, the vertical bus bars are housed inside the internal case that is formed by lower and upper cases of the base module. However, it is possible to install the terminal housing and/or connector receptacle only at the upper case side, and also to install the same at both upper and lower cases. Similarly, when a junction box is vertically positioned, vertical bus bars can be housed in the above terminal housing and/or connector receptacle on either one of bilaterally symmetrical vertical cases of a base module, or on both cases. When the terminal housing and/or connector receptacle that are connected to the external wires are installed at both sides of the cases that grip the vertical bus bars, and both sides of the vertical bus bars are connected to external wires, the external wires can form a spliced connection via the vertical bus bar.
The vertically aligned bus bars are located and held in position by insertion into parallel retainer slots located on the internal surface of one of the case halves that mutually clamp the bus bars in position. Because orifices are provided in the case in the form of the terminal housing and connector receptacle, the non-orifice parts of the case are able to support the vertical bus bars in the above slots, thus forming a structure that allows the wire terminals to connect to the parts of the bus bars exposed through the orifices. Furthermore, a structure may be utilized in which the retainer slots are provided on the internal surfaces of both cases to support both edges of the vertical bus bars.
The vertical bus bars may be formed as one continuous bus bar if they are aligned on the same plane. When a non-continuous circuit is needed, the bus bar is split into multiple bus bars. Therefore, the rectangular vertical bus bars sometimes have different lengths and are aligned in series with spaces therebetween.
One or both of the longitudinal edges of the vertical bus bars that are gripped by the wire terminals may be tapered. This tapered edge makes it easy to insert the vertical bus bar into a slot on an inner surface of the case, and to insert the wire terminal onto the vertical bus bar.
At one part of the base module case, a fuse module is installed to which a fuse attachment part is provided for attaching the fuse. The fuse module also incorporates a fuse bus bar, connecting to a fuse terminal at one end and directly connecting to the vertical bus bar through an aperture in the base module case at the other end.
At one part of the base module case, a relay module is installed, to which a relay attachment for attaching relay, and a relay bus bar, connecting to a relay terminal at one end and directly connecting to the vertical bus bar through an aperture in the base module case at the other end, are provided.
The fuse attachment part of the fuse module and relay attachment part of the relay module join the baseboard of the fuse and relay modules by having case parts that cover the baseboard and form the fuse and relay attachment parts, or by having case parts that form the baseboard molded with the fixed bus bar, having the built-in fuse and relay attachment parts.
The above fuse and relay bus bars are provided with a tab with a grip slot that bends from the fixed part at the baseboard, wherein one side of the tab is formed to grip fuse and relay terminals, and the other side of the tab is formed to grip the edge of the vertical bus bar as described above.
The above fuse module incorporates an insertion part at the terminal of a load side wire that connects to the load side fuse terminal attached to the fuse attachment part, and an input terminal of the fuse connects to the vertical bus bar of the above base module via the fuse bus bar.
Fuse and relay modules can be provided separately as described above, however, they can be combined as a combined fuse/relay module that incorporates fuse and relay attachment parts, and possibly fuse and relay bus bars on a common baseboard. In this case, if there is a need to connect certain fuse and relay bus bar circuits, the bus bars for those circuits are weld connected.
When separately forming fuse and relay modules, one part of the fuse bus bar that is connected to the fuse terminal of the fuse module is extended toward the relay module side, to be connected to the tip of the relay bus bar to which one end of the relay terminal of the relay module is connected.
Furthermore, an electronic control unit can be housed inside the above case, where one end of a relay terminal is connected to a conductor of the electronic control unit, and the other end grips an edge of the vertical bus bar.
In another aspect of the present invention, a junction box is provided that includes an upper case, a lower case, and a plurality of generally rectangular plate-shaped bus bars positioned between the upper case and the lower case, wherein the bus bars are spaced apart and vertically aligned such that upper and lower longitudinal edges of each the bus bar are positioned adjacent a respective one of the upper case and the lower case, and wherein at least one of the upper case and the lower case of the junction box may include multiple terminal housing compartments into which terminals connectable to external wire terminals are insertable, the terminal housing compartments being positioned adjacent selected ones of the bus bars so that terminal grip ends of inserted external wire terminals can grip and connect to the vertical bus bars.
Additionally, the junction box according to the present invention may further include at least one of a fuse module including a fuse connection circuit part and a relay module including a relay connection circuit part, and wherein the fuse connection circuit part and the relay connection circuit part are mountable on one of the upper case and the lower case and are configured to electrically connect to selected ones of the bus bars.
In another aspect of the present invention, the junction box may further include a terminal stopper provided in an inner surface of each terminal housing to lock a terminal connected to the external wire end, upon insertion of the terminal into the terminal housing. Furthermore, the junction box may also include at least one slot provided in one of the upper case and the lower case into which the vertical bus bars are inserted, and may further include a connector receptacle that houses a terminal connected to the external wire terminal, wherein the connector is fitted into a connector receptacle provided in one of the upper case and the lower case, and one of the vertical bus bars is gripped by a pair of grip ends of the terminal inside the connector.
In other aspects of the present invention, the junction box may include a plurality of terminal housings on both the upper case and the lower case, and wherein wire terminals grip both longitudinal sides of the bus bars. Moreover, each bus bar may be configured as at least one of single continuous bus bars and multiple bus bars aligned in series, and at least one longitudinal edge of each the bus bars may be tapered, or both longitudinal edges of the vertical bus bars may be tapered.
Additionally, in another aspect of the present invention, when the terminal housings of the junction box are aligned, one of the upper case and the lower case may include a retainer configured to provide a double stopper for a terminal inserted into the terminal housings.